1. Field of the Invention
The disclosures herein generally relate to an electronic device that is connected to a power source device that includes a power terminal, a ground terminal, and a plurality of data terminals, and a method of an electronic device for determining a type of the power source device.
2. Description of the Related Art
These days, portable devices powered by a rechargeable secondary battery (for example, portable phones, music players and game devices) are becoming popular. Among the portable devices, those are known that have a USB (Universal Serial Bus) interface and charge the secondary battery using power obtained through the USB interface as described in, for example, patent document 1.
In the case of charging a secondary battery through a USB interface, available power is specified in the USB-IF Battery Charging Specification, and the available power can be determined by performing a specified negotiation process.
These days, however, there is a case where a power level that is specified when operating a portable device is inadequate. And so, in the portable device side, ideas for determining a power level that is provided by a connected power source device have been created. In patent document 2, for example, it is described that a voltage of a data line of a USB interface, to which a power source device is connected, is divided, and that a voltage level that is provided by the power source device is determined from the divided voltage.